1. Field of the Invention
This invention relates to a wastewater treating system, more particularly to a wastewater treating system including a vessel partitioned into an activated sludge zone and a coarse filtering zone having a bed of biomass carriers disposed therein.
2. Description of the Related Art
Solid-liquid separation membrane bioreactors have been used in wastewater treatment. The membranes employed in the membrane bioreactors can be ultra-filtration membranes or micro-filtration membranes based on the actual requirements for separating bio-sludge thus formed from the bio-treated wastewater. The solid-liquid separation membranes used in the membrane bioreactors can be classified into a side stream type and an immersed type. Since the concentration of the sludge in a body of the bio-treated wastewater is relatively high, the immersed type solid-liquid separation membrane tends to be easily blocked by the sludge. In addition, since the solid-liquid separation membrane is immersed in the wastewater, the transmembrane pressure of the solid-liquid separation membrane is considerably increased, which results in a decrease in the membrane flux.